AC contactor drive circuit

Abstract

The invention relates to a drive circuit for an AC contactor. The drive circuit for an AC contactor includes a drive circuit input end and a drive circuit output end, wherein the drive circuit input end is connected with a control side AC power supply line; the drive circuit output end is connected with a contactor coil power supply terminal; two rectifier passages are arranged between the drive circuit input end and the drive circuit output end; one of the two rectifier passages is connected with a first rectifier diode, and is connected with a normally closed switch in series; the other rectifier passage is connected with a capacitance-resistance step-down circuit and a bridge rectifier circuit; the drive circuit input end is connected with a relay; the normally closed switch is the normally closed contact for the relay; two ends of a relay coil are connected with an energy storage capacitor in parallel; and a power supply loop on the relay coil is connected with a capacitance charge and discharge circuit. The drive circuit for an AC contactor can independently drive the AC contactor, and realizes that a heavy current triggers undercurrent maintenance, and is simple in the whole structure and low in power dissipation and can effectively protect electric equipment.

Description

technical field [0001] The invention relates to the field of AC contactors, in particular to an AC contactor driving circuit. Background technique [0002] AC contactors are widely used in low-voltage control circuits, and are low-voltage control appliances that are safe to use, easy to control, and stable in performance. After the ordinary AC contactor is pulled in, because there is still AC operating power in the coil, the power consumption is relatively large, the contactor coil will heat up, the insulating layer is easy to age at high temperature, and the life of the AC contactor will be shortened. Instantaneous loss of voltage often occurs in the power grid, that is, the phenomenon of "shocking" in the power grid, and the existing AC contactor often trips and stops due to the instantaneous loss of voltage in the power grid. In addition, when a certain phase of the AC power supply line loses power, the contactor cannot automatically trip. The AC contactor is mainly used...

AI Technical Summary

Problems solved by technology

After the ordinary AC contactor is pulled in, because there is still AC operating power in its coil, the power consumption is relatively large, the contactor coil will heat up, the insulating layer is easy to age at high temperature, and the life of the AC contactor will be shortened

Instantaneous loss of voltage often occurs in the power grid, which is often referred to as the phenomenon of "power shaking" in the power grid. The existing AC contactor often trips and stops due to the instantaneous loss of voltage in the power grid.

In addition, when a certain phase of the AC power supply line is powered off, the contactor cannot automatically trip. The AC contactor is mainly used in the motor control circuit, and the long-term operation of the motor without a phase will cause it to burn out.

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